I am new to the site but have been reading a few of the forum posts trying to discover more.

I am about to build a box for some keepsakes out of combination Jarrah (Australian red hardwood) and English Oak.

The internal dimensions will be approx 355mm x 270mm x 200mm, I was thinking of using 18mm thick boards for the sides and the bottom and top. The long side (front) will be Jarrah with half blind dovetails and the sides in Oak. I was thinking of making the bottom in either Oak or Jarrah (does not matter) and the top out of both type joined together somehow in a decorative way.

I was going to rebate the top and bottom into the sides. and once the box was sealed I would then cut the top off to make the lid.

I just have a couple of questions as I have been reading the forums and some people mention leaving room for the wood to expand. Is this strictly necessary?Also, is it practical to cut the top off to make the lid with a portable circular saw? I do not have a band saw or a table saw.

Depending on your joinery it’s possible for you to have problems with wood movement particularly if your wood is not dry enough to start with. 6-8 percent. sealing the end grain of the top and bottom with a couple coats of shellac should help minimize how much moisture the top and bottom will take on. I think cutting the top of with a circular saw will be difficult and perhaps unsafe. Another option might be to use a router table with a small bit perhaps a 1/4” OR less. It’s also possible with a sharp hand saw with fine teeth. If you try any of these approaches I would strongly urge you to practice on scrap wood first.

I was going to leave the wood under the bed in the house for a while to make sure it was as dry as possible, but after reading some more, I think I am going to have to try and design a bit more for the movement. I can’t think of a way yet to design a flush fitted top that sits inside the sides, which is how I wanted it to look. I may decide to make a mitered panel top. Would that allow for enough movement if I still wanted to rebate the finished panel into the top? Or would the mitered frame also expand and contract too much?

I have also got some cheaper softwood to basically make a replica box (or 2) to practise the first time, so I will try a few different things out.

Thanks JAAune, those blogs are particulalry helpful for visualising the effects of movement.

Re hand sawing the top off, I did not think I would be able to be accurate enough or square enough as the last time I made a box similar to this was more than 10 years ago. I will give it a try though. Incidentally madts, I ordered a Japanese pull saw last week and it should be with me in a week or so, so I’ll give that a go too.

I use both a table saw and a handsaw to cut the tops off my boxes. What I do is slice all the way through both sides and most of the way through the thickness of the ends. The handsaw is used to slice through through the remaining 1/8” or so of wood that still holds to two halves of the box together. Chisels, handplanes or a similar tool gets used to finish cleaning up.

Mitered frames work well assuming the frame members aren’t too wide and the joints are reinforced with some sort of joinery and not just glued together. The main thing to be aware of when doing mitered frames is that the joints can show gaps if the frame members are too wide due to expansion/contraction issues. However, if your frame parts are under 3” wide, the joints are reinforced well with tenons or biscuits or some sort of interlocking joinery, the joints shouldn’t show gaps over time (assuming they were tight to begin with and properly glued).

I should probably add the miter joint issue to my blog page since it’s a small detail that is nice to know.

I can think of a design that would achieve the look of a flush fitted top but is really a frame and panel. I’ll sketch something up later tonight.

It basically puts the majority of the frame under the panel instead of around the side. This would make it possible to create a stable panel that could fit inside a box and always keep the same gap between it and the box regardless of moisture content.

I didn’t bother with dimensions. That depends quite a bit on the overall size of the box, species of wood, etc.

Thanks JAAune. I think I get what you mean so I went and drew something up in sketchup to try and visualise how it might be.This first picture shows the mitre joint of the top panel with the biscuit hole and the slots for fitting into the end panel of the box. With the idea that the edge of the top panel meets with the edge of the box flush. I will have to use a slot bit on the router. The dimensions of the mitred panel frame will be 18mm x 45mm hardwood.

The second picture shows the same slot cut into the top of the side panel. Again cut with a slot router bit and a straight or rebate bit.

The 3rd picture shows a possible design for the inside of the panel top, and how it will fit into the frame of the panel.

I essentially thought I would glue in the center of the frame panel on each end to the box ends but not down the sides, so that the wood could move side ways out from the center. Does it look like I am over complicating for a box this size? Do I only really need to allow for movement on the inside of the panel and not the outside, thereby not needing to cut slots in the box frame but just use a rebate bit. Apologies if I have made things more confusing. Looks like I may not even be able to get Jarrah in the UK now so I will have to get my brother to send me some from Australia.

Thanks, that is very simple and straight to the point. I never have either on other boxes but this one is for a special memento and I did not start worrying about it until I started doing more research.